Waiting times to get MRI scans in Taranaki are among the worst in the country, the Labour Party claims.

Health spokeswoman Annette King and list MP Andrew Little are urging Health Minister Tony Ryall to ease up the pressure being put on meeting other public health targets.

They say these targets, such as elective surgery and waiting times in the emergency department, are being met to the detriment of other areas of health.

But Fulford Radiology chairman and TDHB board member Flora Gilkison said DHBs were reporting their results in different formats and when Taranaki was compared with others it was not necessarily apples with apples.

The waiting times for diagnostic procedures across the country were revealed in an official information request to the 20 DHBs by Mrs King. She tabled these in Parliament last week.

Mr Little said the 34-week waiting times for routine MRIs in Taranaki was a cause for concern.

Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to visualise internal structures of the body.

Mr Little was arranging a meeting with the DHB in the next week or so to discuss the situation.

Acute and urgent scans were being carried out immediately which was consistent with what was happening in the rest of the country but for the remainder there were significant issues for people.

"To have to go 34 weeks with discomfort is plainly unacceptable and the DHB has to get on top of it," he said.

Because the DHB was reliant on the provider, Fulford Radiology, the DHB must take a closer interest and ensure it was actively trying to improve the waiting times, he said.

Dr Gilkison said said they were experiencing a large increase in demand for diagnostics and were doing what they could to improve efficiency.

MRIs had increased 36 per cent per 1000 people from 2005-6 to 2011-12, while CT scans had a 95 per cent increase and ultrasounds were up by 45 per cent in the same time, she said.

With CTs, 86 per cent were accepted and scanned during the same month.

At the same time, Taranaki had only one MRI machine and one CT and was still to find a replacement for one radiologist.

As a result Taranaki was now on the cusp of having to buy a second MRI, she said.

The machines were being used seven days a week "so there is only so much that can be done".

By improving its processes, Fulford had increased its efficiency by 25 per cent, she said.

Recruitment was always going to be an issue for the service.

Reporting results were in their infancy and would get a lot better in future, she said. "It will get better in the way it's reported."